Changes of urinary L-FABP, KIM-1, NGAL and serum cystatin C in diabetic nephropathy and its clinical value

Abstract

Objective To investigate the changes of urinary liver-type fatty acid binding protein(L-FABP), kidney injury molecule-1(KIM-1), neutrophil gelatinase-associated lipocalin(NGAL)and serum cystatin C in diabetic nephropathy and its clinical value. Methods A total of 118 patients diagnosed with type 2 diabetes in the Department of Endocrinology of Affiliated Hospital of Sichuan Medical University from October 2011 to October 2012 were recruited in this study. According to their urinary albumin-to-creatinine ratio(UACR), patients were divided into normal albuminuria group(n=45), microalbuminuria group(n=42), and macroalbuminuria group(n=43). A total of 41 healthy subjects were enrolled as normal control group(n=41). Enzyme-linked immunosorbent assays were used to measure the levels of urinary L-FABP, KIM-1 and NGAL.Turbidimetric inhibition immuno-assay was used to measure the expression of serum cystatin C. All the urinary indicators were adjusted by the level of urine creatinine. Changes of biomarkers in each group and their crrelations between UACR, eGFR were also compared. Results Compared with normal control group, urinary L-FABP and serum cystatin C were significantly increased in diabetic groups (χ2=77.959, 104.003, all P<0.05); urinary KIM-1 was also significantly increased (χ2=29.711, P<0.05). Urinary NGAL was increased in microalbuminuria group and macroalbuminuria group compared with normal control group and normal albuminuria group(χ2 =23.833, P<0.05), but there were no significant difference between normal albuminuria group and normal control group. Urinary L-FABP, KIM-1, NGAL and serum cystatin C were positively correlated with UACR(r=0.719, 0.427, 0.327, 0.726, all P<0.01); while L-FABP and serum cystatin C were negatively correlated with eGFR(r=-0.301, -0.791, all P<0.01). Conclusion Urinary L-FABP, KIM-1, NGAL and serum cystatin C are increased in early diabetic nephropathy, while urinary L-FABP and serum cystatin C may be the better biomarkers to predict diabetic renal injury. Key words: Diabetic nephropathy; Liver-type fatty acid binding protein; Kidney injury molecule-1; Neutrophil gelatinase-associated lipocalin; Serum cystatin C